Any discussion of the background art throughout the specification should in no way be considered as an admission that such background art is prior art nor that such background art is widely known or forms part of the common general knowledge in the field.
Conventional sit-up exercises performed on a flat surface such as the floor or a matt are notoriously famous for causing discomfort in the exerciser, particularly in their lower back and tail bone, since the back is not supported during the exercise.
As an alternative, sit-up exercises can be performed on an exercise ball to provide support to the exerciser's back. However, due to the arching of the back and that in position on the exercise ball, the exerciser's thighs are parallel to the torso which, again, puts undue strain on the lower back. Also, the range of motion of the exercise is restricted when using an exercise ball as the users' legs are not secured and the risk of overbalancing increases as the upper body extends through a full back arch.